Helianthus arizonensis
(Arizona sunflower)
[taxon report][distribution map][photos][line drawing]
Family: Asteraceae
Scientific Name: Helianthus arizonensis R.C. Jackson
Synonyms: None
Vernacular Name: Arizona sunflower
R-E-D Code: 2-1-2
Description: Herbaceous perennial with long creeping roots that function like rhizones; stems glabrous, glaucous, 20-30 cm tall; leaves opposite, sessile, lanceolate, 6-7 cm long, 1.0-1.3 cm wide, tip acute, margins undulate, surface glabrous and glaucous, bluish-green; heads one to few; disk 1.0-1.8 cm in diameter; phyllaries lanceolate, ciliate on margins, glabrous to puberulent on backs, 2.0-2.7 mm broad; rays yellow, few, small; disk corollas yellow; pales acute, entire; pappus of 2 ovate scales; achenes about 3 mm long. Flowers June through August.
Similar Species: Helianthus ciliaris (blueweed) also has stems and leaves that are glaucous and bluish-green, but it is usually 40-70 cm tall and its disk corollas are red or reddish-tipped. Helianthus laciniatus has stems that are usually hispid or strigose and leaves that are glabrous to strigose and ashy green to light green in color.
Distribution: New Mexico, Catron County, west of Quemado; Arizona, Coconino and Navajo counties.
Habitat: Dry, frequently sandy soil at 1,200-2,100 m (4,000-7,000 ft).
Remarks: The rare Helianthus arizonensis is a diploid species (n=17) while the closely related and common H. ciliaris is tetraploid (n=34).
Conservation Considerations: This species is poorly known. Additional field searches are needed to determine range, abundance, habitat, reproduction and other important biological parameters.
Important Literature (*Illustration):
*Heiser, C.B., D.M. Smith, S.B. Clevenger and W.C. Martin. 1969. The North American sunflowers (Helianthus). Memoirs of the Torrey Botanical Club 22(3):1-220.
Jackson, R.C. 1963. Cytotaxonomy of Helianthus ciliaris and related species of the southwestern U.S. and Mexico. Brittonia 15:260-271.
Information Compiled By: Charlie McDonald, 1999
Agency Status:
